Fabrication And Application Of Electrochemical Immunosensor For Multiple Tumour Biomarkers

Electrochemical immunosensor is a kind of biosensor which has a lot of advantages including high sensitivity,fast analysis and simple operation.Recently years,simultaneous detection electrochemical immunosensor of multiple tumour biomarkers has been widely applied in electrochemical field because of the boundedness of the single tumour biomarker analysis in clinical application.This paper has been discussed about the application of graphene,carbon nanotubes,gold nanoparticles,silica,ZnO nanorod and polypyrrole in multiple tumour biomarkers detection.The paper contains four chapters as follows:Chapter 1: A review about the types and the advanced research of electrochemical sensors.Chapter 2: We have fabricated a simultaneous electrochemical immunosensing of alpha-fetoprotein and prostate specific antigen using silica nanospheres coated with gold nanoparticles(Si@Au NPs)as the label.Graphene was firstly dropped on bare glass carbon electrode.Then gold particles were electrodeposited on the surface of graphene decorated electrode.And capture antibody was immobilized on the surface of electrode through the interaction between antibody and gold nanoparticles.A sandwich type structure was formed when the Si@Au NPs nanocomposite decorated with amount of secondary antibodies labeled with signal probes(Azure A and ferrocenecarboxylic acid)was immobilized on the surface of electrode through antigen-antibody specific identification.Different pulse voltammetry(DPV)was used to obtain the response signal from Azure A and ferrocenecarboxylic acid and the relationship between the signal intensity and the corresponding tumour biomarker.Electroactive substance,selected as the signal probes in this immunosensor,whose signals are more stable and do not overlap eachother.This immunosensor displayed good analytical performance such as sensitivity.Chapter 3: We have fabricated a simultaneous determination immunosensor for the detection of carcinoembryonic antigen and alpha-fetoprotein based on metal ions loaded ZnO nanorod wrapped polydopamine for signal amplification.The detection range of the immunosensor has been improved.Chapter 4: We have fabricated a sensitive immunosensor for the detection of carcinoembryonic antigen and alpha-fetoprotein using functioned polypyrrole nanosphere as the label.On the base of the former work,conductive polymer nanomaterial was applied into sensing design.Signal probes were immediately immobilized on the surface of polymer nanomaterial through ?-? aromatic interactions,which avoid the lost of partial activity for antibody when it was covalent bonded with signal probes.As a result,the analytic property of this immunosensor was further improved.